1. Technical Field of the Invention
The present invention concerns a sheet shaped key top composed of integrally formed key top and sheet, constituting various press-button switches for various mobile communication equipment such as cellular phone, car phone, or the like, fixed telephone set, personal computer, controller, AV equipment, motor input switch or the like, and a manufacturing method thereof.
2. Prior Art
In recent years, according to minimization and mobilization of electric and electronic equipment, it is also required to miniaturize, and to reduce the thickness and weight of press-button switches used for their operation section.
To respond to this demand, conventionally, as shown in FIG. 14, it has been known a sheet shaped key top, wherein sheet and key top are formed integrally, by printing a display section 15 of predetermined characters and patterns at the surface or back of a sheet 21 made of flexible synthetic resin, bending this sheet 21 to the same shape as the top face of the key top element, and at the same time, directly heat fusing a key top element 17 made of thermoplastic injected in the bent portion, or fixing the key top element in the bent portion of this sheet with adhesive.
Conventionally, this kind of sheet shaped key top has be decorated only by printing on the sheet, and it has been impossible to respond to market needs such as metallic plating tone or complicated key top shape.
On the other hand, a key sheet wherein a molded rigid resin key top is glued on and integrated with a key pad. The rigid resin key top may presents a variety of decoration for the display section; however, the number of manufacturing process increased and it tended to make difficult to reduce the cost, because it is adhered to a flexible key pad made of elastic sheet such as elastomer or resin film. Moreover, there was no other means but to combine as another part, to form a pusher made of rigid resin under the key pad, lowering the production efficiency.
Still further, characters and patterns were easily enlarged or distorted, predetermined characters and patterns were printed on a sheet made of synthetic resin film, and then the sheet was bent upward with a thermoplastic resin under a high temperature and a high pressure. Moreover, in this composition, it was difficult to obtain those of a small interval between adjacent key tops, those with a high key top, or those of complicated shape, in respect of the forming.
In order to solve the aforementioned problems, the present invention intends to provide a sheet shaped key top allowing to facilitate the key top positioning, stabilize the character and pattern quality of the display section, facilitate to diversify the key top design of coating layer, metal plating layer or the like, and at the same time, increase the production efficiency, and a manufacturing method thereof.
Moreover, it concerns a sheet shaped key top, composed by arranging a plurality of molded resin key tops on a single sheet, wherein at least one resin key top is fitted so as to cover the top of a core passing through the sheet.
Further, it concerns a sheet shaped key top, wherein a tip placed at a bottom of the core sheet is a pusher.
Still further, it concerns a sheet shaped key top, wherein the core and the resin key top are adhered with translucent adhesive.
Still further, it concerns a sheet shaped key top, wherein the core and the resin key top are made of thermoplastic resin or thermoplastic elastomer.
Still further, it concerns a sheet shaped key top, wherein the sheet is made of synthetic resin film and a core section is made of thermoplastic resin.
Still further, it concerns a illuminating sheet shaped key top, having a character illumination type key top display section wherein a predetermined character and pattern section is translucent while the part other than the predetermined character and pattern section is not translucent.
Still further, it concerns a illuminating sheet shaped key top, wherein the non translucent part of the key top display section is a plated layer of metal plating.
Still further, it concerns a illuminating sheet shaped key top, wherein the non translucent part of the key top display section is a coated layer of non translucent paint.
Also, it concerns a manufacturing method of a sheet shaped key top composed by arranging a molded resin key top on a sheet, comprising steps of pinching a sheet in a die, injecting thermoplastic resin or thermoplastic elastomer passing through the sheet from the surface side or back side of the sheet, forming a core integrated with the sheet, removing from the die, and fitting the resin key top so as to cover the upper portion of the core situated at the top of the sheet.
Further, it concerns a manufacturing method of a sheet shaped key top composed by arranging a molded resin key top on a sheet, comprising steps of bending the sheet to the same form as the top face of a key top element, pinching in a die so as to direct the bent portion to the top face side of the key top element, injection-molding the key top element with thermoplastic resin or thermoplastic elastomer, and at the same time, molding a core integrated with the sheet, by injecting thermoplastic resin or thermoplastic elastomer passing through the sheet from the back side of the sheet, removing from the die, and covering the upper portion of the core situated at the top of the sheet with resin key top.
Still further, it concerns a manufacturing method of a sheet shaped key top composed by arranging a molded resin key top on a sheet, comprising steps of setting the resin key top in a cavity of the die of the sheet surface side, injection-molding a core with thermoplastic resin or thermoplastic elastomer from the back side of the sheet pinched by the sheet, and integrating the sheet, core and resin key top in the die.
Still further, it concerns a manufacturing method of a sheet shaped key top composed by arranging a molded resin key top on a sheet, comprising steps of setting the resin key top in a cavity of the die of the sheet surface side, further, bending the sheet having a display section to the same form as the top face of the key top element, pinching in a die so as to direct the bent portion to the top face side of the key top element, integrating the sheet and the key top element by injection-molding the key top element with thermoplastic resin or thermoplastic elastomer, and at the same time, injection-molding the core passing through the sheet from the back side of the sheet, and integrating the sheet, core and resin key top in the die.
By the way, the sheet is preferably provided with a least one hole as the position where the core section is to be formed. The shape thereof is not particularly limited and it may be a round or square hole, or a simple cruciform notch.